In general, a blood purification apparatus for performing hemodialysis treatment includes an arterial blood circuit and a venous blood circuit that constitute a blood circuit for extracorporeally circulating the blood of a patient, a blood purifier for purifying the blood extracorporeally circulated by the blood circuit, and a device provided with various treatment means such as a blood pump for performing blood purification treatment by the blood circuit and the blood purifier. An arterial puncture needle and a venous puncture needle are attachable to the leading ends of the arterial blood circuit and the venous blood circuit.
After the arterial puncture needle and the venous puncture needle are inserted in a patient, a blood pump is driven, thereby causing the blood of a patient to flow in the arterial blood circuit and the venous blood circuit, and in the process of the flowing, blood purification is performed by the blood purifier. Also, in hemodialysis treatment, a dialysate introduction line for introducing dialysate into the blood purifier, and a dialysate discharge line for discharging dialysate from the blood purifier are each connected to the blood purifier.
In blood purification treatment, there are established treatments: hemodialysis treatment (HD) in which dialysate is caused to flow through a dialysate flow path of the blood purifier, and substances in the blood are thereby removed by a diffusion effect via a blood purification membrane; hemofiltration treatment (HF) in which water and substances in the blood are removed by an effect of ultrafiltration pressure in the blood purifier, and a substitution solution equivalent in amount to the removed water is injected into the blood; and hemodiafiltration (HDF) in which hemodialysis treatment (HD) and hemofiltration treatment (HF) are performed concurrently. Particularly when blood purification treatment is performed on a patient having a disorder such as acute renal failure, it is necessary to switch between and perform one of hemodialysis (HD), hemofiltration (HF) and hemodiafiltration (HDF) according to the conditions of the patient in a treatment process.
Also, in hemofiltration treatment (HF) and hemodiafiltration treatment (HDF), dilution is performed which is variously selected from: pre-dilution in which a substitution solution is injected into the upstream side (the arterial blood circuit) of the blood purifier; post-dilution in which a substitution solution is injected into the downstream side (the venous blood circuit) of the blood purifier; and pre and post-dilution in which a substitution solution is injected into both the upstream side and downstream side (the arterial blood circuit and the venous blood circuit). Thus, nowadays, a blood purification apparatus capable of switching between hemodialysis treatment (HD), hemofiltration treatment (HF), and hemodiafiltration treatment (HDF) and selecting any from pre-dilution, post-dilution, and pre and post-dilution is called for.
To cope with such needs, a blood purification apparatus has been proposed in the past that includes a plurality of dialysate supply lines branching from a dialysate introduction line and connected to a blood circuit, liquid delivery pumps and a plurality of electromagnetic valves disposed in each of the dialysate supply lines, the blood purification apparatus being capable of switching between hemodialysis treatment (HD), hemofiltration treatment (HF), and hemodiafiltration treatment (HDF) as well as selecting from pre-dilution, post-dilution and pre and post-dilution by connecting the leading end of each dialysate supply line to a predetermined portion of the blood circuit according to a treatment type then supplying the dialysate of the dialysate introduction line to the blood circuit as a substitution solution. It is to be noted that such prior art is not related to an invention with publicly known literature, thus there is no information on prior art literature to be cited.